The present invention relates to the feeding of sheet material such as paper.
Thus, the present invention is particularly appplicable to the feeding of paper in a machine which supplies corrugated paper. With machines of this general type the sheet material is derived from rolls of the sheet material, with the sheet material being unwound from the rolls during the feeding of the sheet material. Thus, when one roll has been almost completely unwound it is necessary to connect the sheet material thereof to the leading end of the sheet material from a second roll, in order to provide in this way a continuous feeding of the sheet material.
However, the above operations are accompanied by problems which up to the present time have not been satisfactorily solved. These problems arise from the fact that a sheet material such as paper is not rolled in a standardized manner. Thus such sheet material has a front surface and a rear surface and some manufacturers supply the sheet material in rolls where the front surface is directed inwardly toward the axis of the roll whereas other manufacturers supply such rolls with the front surface directed outwardly away from the axis of the roll. As a result, it often happens that the front surfaces of the sheet material are reversed when connecting a web from one roll to the web from the preceding roll. The result is that the exterior surface of the final product has an irregular appearance which is highly undesirable.
It is known to carry out operations of the above type manually. The manual joining of the leading end of sheet material from one roll to the trailing end of sheet material from an exhausted roll requires operations such as cutting the sheet material issuing from the roll which is about to be exhausted and then making a connection to the leading end of the sheet material from the new roll. These operations when manually carried out require a considerable amount of skill in order to achieve the effective connections while avoiding waste of large amounts of sheet material. Moreover it is necessary in connection with such manual operations either to terminate the feed or to temporarily reduce the feed velocity of the sheet material so as to enable the change of the supply from one roll to the next to be carried out while avoiding undesirably large amounts of residual sheet material on a replaced roll. This termination or reduction in the speed with which the sheet material is fed may result in a loss of quality in the final product. This latter fault is likely to be encountered particularly with products which are dried, as is the case with corrugated paper, inasmuch as the slowing down of the operations easily results in over-drying of the product.
Elimination of problems of the above type is particularly important in view of the fact that in recent times the production speed in the manufacture of material such as corrugated paper has been greatly increased, and thus it is essential to avoid the above problems in order to be able to achieve a uniform standardized product of high quality.